Based in Cardiff Bay, it has control of areas including health, education, language, culture and public services.

Under the devolution process started by Tony Blair’s administration in 1997, Westminster retained control of UK-wide policy on defence, foreign policy and benefits.

When asked whether they felt devolution had improved the way Wales is governed, 34 per cent said they thought it had but 46 per cent thought it had “not made much difference”.

Further questioning exposed a deep perceived divide in the country, with 31 per cent seeing the south-east of Wales getting the greatest benefits, compared to 4 per cent citing north Wales and 1% mid-Wales.

Professor Roger Scully from Cardiff University’s Wales Governance Centre told the BBC the figures were “not great” in terms of public understanding.

“I think that it does show there is still a lot of confusion amongst people about exactly where the line for responsibility comes between London and Cardiff Bay in terms of governance,” he added.

“Beyond [education], people have some general sense that there is a devolved government in Wales, there is a government in London, but exactly who does what and why, I think the details of that largely elude them.”

The two administrations have been rowing about standards in the Welsh NHS after David Cameron said care was so bad in some hospitals that the England’s border along Offa’s Dyke was the “line between life and death”.

The Welsh Government claimed its budget had been cut by Westminster and said services were dealing with rising demand.

There have also been calls for policing powers to be transferred to the Welsh Assembly.

The introduction of a devolved Welsh Government was controversial after a turnout of just 50.1 per cent of the electorate and a 50.3 per cent “yes” vote meant that only a quarter of residents supported a devolved government in the 1997 referendum.

In Scotland, by contrast, 74 per cent of people voted “yes” and the turnout was 60 per cent.

The poll was conducted for BBC Wales by ICM Research, who interviewed a random sample of 1,004 in May.